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Deepcool PQ850M Power Supply Review

The Deepcool PQ850M achieves decent performance and it is silent.

Deepcool PQ850M
(Image: © Tom's Hardware)

Protection Features

Check out our PSUs 101 article to learn more about PSU protection features.

OCP (Cold @ 26°C)12V: 99.6A (141.71%), 12.102V
5V: 27.3A (136.5%), 5.019V
3.3V: 26.8A (134%), 3.338V
5VSB: 6.3A (210%), 4.971V
OCP (Hot @ 43°C)12V: 83.2A (118.86%), 12.033V
5V: 27.2A (136%), 4.990V
3.3V: 26.6A (133%), 3.314V
5VSB: 6.2A (206.67%), 4.952V
OPP (Cold @ 27°C)1200.61W (142.93%)
OPP (Hot @ 43°C)1001.06W (119.17%)
OTP✓ (147°C @ secondary side)
SCP12V to Earth: ✓
5V to Earth: ✓
3.3V to Earth: ✓
5VSB to Earth: ✓
-12V to Earth: ✓
PWR_OKAccurate but lower than 16ms
NLO
SIPSurge: MOV
Inrush: NTC Thermistor & Bypass relay

The OCP triggering points at low temperatures are higher than usual, but this doesn't affect the PSU's operation. With increased temperatures, OCP at 12V drops notably lower, protecting the platform more effectively. The same goes for OPP. At low temperatures, it is pretty high, while with increased ambient, it drops 200W lower. We don't usually see so much difference in OCP and OPP under cold and hot conditions. 

DC Power Sequencing

According to Intel’s most recent Power Supply Design Guide (revision 1.4), the +12V and 5V outputs must be equal to or greater than the 3.3V rail at all times. Unfortunately, Intel doesn't mention why it is so important to always keep the 3.3V rail's voltage lower than the levels of the other two outputs.

No problems here since the 3.3V rail is always lower than the other two. 

Cross Load Tests

To generate the following charts, we set our loaders to auto mode through custom-made software before trying more than 25,000 possible load combinations with the +12V, 5V, and 3.3V rails. The deviations in each of the charts below are calculated by taking the nominal values of the rails (12V, 5V, and 3.3V) as point zero. The ambient temperature during testing was between 30 to 32 degrees Celsius (86 to 89.6 degrees Fahrenheit).

Load Regulation Charts

Efficiency Graph

(Image credit: Tom's Hardware)

Ripple Graphs

The lower the power supply's ripple, the more stable the system will be and less stress will also be applied to its components.

Infrared Images

We apply a half-load for 10 minutes with the PSU's top cover and cooling fan removed before taking photos with a modified Fluke Ti480 PRO camera able to deliver an IR resolution of 640x480 (307,200 pixels).

Without active cooling, the boost diode gets hot, very hot. This is strange since it is firmly secured on the APFC heat sink, using a thermal pad for better contact. Nonetheless, this diode can handle 8A with 125 degrees Celsius junction temperature. 

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Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.

  • Co BIY
    This category seems to show all the competitors neck-and-neck. Are they all using the SeaSonic Gold Platform ?

    I don't mind the grid pattern and perhaps it's excellent airflow allowed for less fan.

    I think it looks particularly sharp on the back.
    Reply
  • drajitsh
    It is not ideal to buy a PSU right now because we are in a transition phase from the previous ATX spec to the new one. I am likely going to be forced to buy 2 systems for my office. They will have integrated graphics to start with and will be upgraded to low end discrete graphics in 1-2 years. Does your recommendation still stand?
    Reply
  • Co BIY
    drajitsh said:
    It is not ideal to buy a PSU right now because we are in a transition phase from the previous ATX spec to the new one. I am likely going to be forced to buy 2 systems for my office. They will have integrated graphics to start with and will be upgraded to low end discrete graphics in 1-2 years. Does your recommendation still stand?

    I don't think low end cards will be requiring the new connectors in the short term. This is a necessity only for the high end cards with crazy peak power draws.

    The makers of the low end cards will also build them to match the likely customer , you and the other 500 million people running machines without the ATX3.0 PSU upgrades.

    Question: Why are PSU's built with fan grills ? None of the other fans in PCs have grills and PSU fans aren't bigger or faster . Also readily replaceable fans could be a great selling point because users want to mod.
    Reply
  • Tom Sunday
    The old story...eveyone wants a piece of the pie! Deepcool once dedicated exclusively for PC cooling now into PSU's as well. Next we have Seasonic making memory. I wish that companies would perfect theiroriginally intended product line and giving us those results, instead of just plastering their nane on products made by others. I have no respect for this as it is a quick fix to make more money and even having some people believe that they have a better product when this is absolutely not the case .
    Reply
  • Co BIY
    Tom Sunday said:
    The old story...eveyone wants a piece of the pie! Deepcool once dedicated exclusively for PC cooling now into PSU's as well. Next we have Seasonic making memory. I wish that companies would perfect their originally intended product line and giving us those results, instead of just plastering their nane on products made by others. I have no respect for this as it is a quick fix to make more money and even having some people believe that they have a better product when this is absolutely not the case .

    I agree with you if they just slap their "Premium" name and a few RGB's to something of below average quality and then throw it out there at a Premium price.

    In this case they started with a very solid platform, executed it competently and it delivers the goods quietly.

    This PSU doesn't seem like it's worth getting the pitchforks out for.
    Reply
  • Tom Sunday
    Co BIY said:
    This PSU doesn't seem like it's worth getting the pitchforks out for.

    Yes you are on the point as always! My other 'Deepcool' thought and great hope was that someday perhaps air-cooling products will equal the thermal performance of AIO’s. In part many users even with extensive experience sometimes have trouble installing AIO’s into their case. Of course for the time being the sheer profits (or in Asetek’s case the patent license fees to other manufacturers) by keeping on manufacturing AIO’s is much more profitable. Hence perhaps stifling the development or serious further $$$ investments into the ‘inventiveness’ of air-cooling. Amazing though the AIO Asetek patent, filed in November 2004 has never been significantly improved upon and just basically copied over and over again. Of course and just perhaps further CPU development in the years ahead may offer whereby no CPU cooling will ever be necessary. That would of course be the best of both worlds!
    Reply
  • Co BIY
    Tom Sunday said:
    Yes you are on the point as always!

    Thank You for the compliment!

    Tom Sunday said:
    My other 'Deepcool' thought and great hope was that someday perhaps air-cooling products will equal the thermal performance of AIO’s. In part many users even with extensive experience sometimes have trouble installing AIO’s into their case.

    I agree with you that the simplicity, reliability and cost advantages of air cooling justify continued development. Lenovo has an interesting offset stacked air cooler design on their new Threadripper workstations that I would like to see make it to the DIY market .


    Lenovo Thinkstation P620 Review (at Anandtech)
    Reply